Other Parts Discussed in Thread: MOTORWARE
Hi,
we have developed a custom inverter based on the F280049 processor and the c2000 motor control sdk libraries for a high power inverter (200kW peak) driving a high power motor (200kW). Nominal DC voltage is 700V and maximum phase current is 450Arms (we use hall effect sensors). I have two separate, possibly unrelated, questions:
- The inverter works reasonably well at medium to low current levels but when getting close to full current (450Arms), the system controller gets very oscillatory or unstable until the point the current exceeds the trip level (800Amps peak) and the inverter goes into fault. I believe this is due to the motor iron reaching saturation which changes the characteristics of the system thus affecting the controller and instabilities. Is there any way to improve the controller to deal with this situations?
- Our application requires the inverter to be stable even with variations of the input DC voltage (which can range from 700V down to 500V). We have noticed that the stability and controllability of the system is affected by variations on the DC voltage. Is there a way to compensate for this? I remember, before C2000 motor control sdk, when motorware existed there was an option named "DC voltage compensation". If I remember correctly, such option would modify the Kp gains to the current controller depending on the DC voltage, I don't know if this is the kind of thing I am looking for? or is this something else? I haven't seen such thing on the C2000 motor control labs. Would this help?
Some help would be very much appreciated. Thanks.